bfd/binary.c

   1 /* BFD back-end for binary objects.
   2    Copyright 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001
   3    Free Software Foundation, Inc.
   4    Written by Ian Lance Taylor, Cygnus Support, <ian@cygnus.com>
   5
   6 This file is part of BFD, the Binary File Descriptor library.
   7
   8 This program is free software; you can redistribute it and/or modify
   9 it under the terms of the GNU General Public License as published by
  10 the Free Software Foundation; either version 2 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU General Public License for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with this program; if not, write to the Free Software
  20 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.  */
  21
  22 /* This is a BFD backend which may be used to write binary objects.
  23    It may only be used for output, not input.  The intention is that
  24    this may be used as an output format for objcopy in order to
  25    generate raw binary data.
  26
  27    This is very simple.  The only complication is that the real data
  28    will start at some address X, and in some cases we will not want to
  29    include X zeroes just to get to that point.  Since the start
  30    address is not meaningful for this object file format, we use it
  31    instead to indicate the number of zeroes to skip at the start of
  32    the file.  objcopy cooperates by specially setting the start
  33    address to zero by default.  */
  34
  35 #include <ctype.h>
  36
  37 #include "bfd.h"
  38 #include "sysdep.h"
  39 #include "libbfd.h"
  40
  41 /* Any bfd we create by reading a binary file has three symbols:
  42    a start symbol, an end symbol, and an absolute length symbol.  */
  43 #define BIN_SYMS 3
  44
  45 static boolean binary_mkobject PARAMS ((bfd *));
  46 static const bfd_target *binary_object_p PARAMS ((bfd *));
  47 static boolean binary_get_section_contents
  48   PARAMS ((bfd *, asection *, PTR, file_ptr, bfd_size_type));
  49 static long binary_get_symtab_upper_bound PARAMS ((bfd *));
  50 static char *mangle_name PARAMS ((bfd *, char *));
  51 static long binary_get_symtab PARAMS ((bfd *, asymbol **));
  52 static asymbol *binary_make_empty_symbol PARAMS ((bfd *));
  53 static void binary_get_symbol_info PARAMS ((bfd *, asymbol *, symbol_info *));
  54 static boolean binary_set_section_contents
  55   PARAMS ((bfd *, asection *, PTR, file_ptr, bfd_size_type));
  56 static int binary_sizeof_headers PARAMS ((bfd *, boolean));
  57
  58 /* Set by external programs - specifies the BFD architecture
  59    to use when creating binary BFDs.  */
  60 enum bfd_architecture bfd_external_binary_architecture = bfd_arch_unknown;
  61
  62 /* Create a binary object.  Invoked via bfd_set_format.  */
  63
  64 static boolean
  65 binary_mkobject (abfd)
  66      bfd *abfd ATTRIBUTE_UNUSED;
  67 {
  68   return true;
  69 }
  70
  71 /* Any file may be considered to be a binary file, provided the target
  72    was not defaulted.  That is, it must be explicitly specified as
  73    being binary.  */
  74
  75 static const bfd_target *
  76 binary_object_p (abfd)
  77      bfd *abfd;
  78 {
  79   struct stat statbuf;
  80   asection *sec;
  81
  82   if (abfd->target_defaulted)
  83     {
  84       bfd_set_error (bfd_error_wrong_format);
  85       return NULL;
  86     }
  87
  88   abfd->symcount = BIN_SYMS;
  89
  90   /* Find the file size.  */
  91   if (bfd_stat (abfd, &statbuf) < 0)
  92     {
  93       bfd_set_error (bfd_error_system_call);
  94       return NULL;
  95     }
  96
  97   /* One data section.  */
  98   sec = bfd_make_section (abfd, ".data");
  99   if (sec == NULL)
 100     return NULL;
 101   sec->flags = SEC_ALLOC | SEC_LOAD | SEC_DATA | SEC_HAS_CONTENTS;
 102   sec->vma = 0;
 103   sec->_raw_size = statbuf.st_size;
 104   sec->filepos = 0;
 105
 106   abfd->tdata.any = (PTR) sec;
 107
 108   if (bfd_get_arch_info (abfd) != NULL)
 109     {
 110       if ((bfd_get_arch_info (abfd)->arch == bfd_arch_unknown)
 111           && (bfd_external_binary_architecture != bfd_arch_unknown))
 112         bfd_set_arch_info (abfd, bfd_lookup_arch (bfd_external_binary_architecture, 0));
 113     }
 114
 115   return abfd->xvec;
 116 }
 117
 118 #define binary_close_and_cleanup _bfd_generic_close_and_cleanup
 119 #define binary_bfd_free_cached_info _bfd_generic_bfd_free_cached_info
 120 #define binary_new_section_hook _bfd_generic_new_section_hook
 121
 122 /* Get contents of the only section.  */
 123
 124 static boolean
 125 binary_get_section_contents (abfd, section, location, offset, count)
 126      bfd *abfd;
 127      asection *section ATTRIBUTE_UNUSED;
 128      PTR location;
 129      file_ptr offset;
 130      bfd_size_type count;
 131 {
 132   if (bfd_seek (abfd, offset, SEEK_SET) != 0
 133       || bfd_bread (location, count, abfd) != count)
 134     return false;
 135   return true;
 136 }
 137
 138 /* Return the amount of memory needed to read the symbol table.  */
 139
 140 static long
 141 binary_get_symtab_upper_bound (abfd)
 142      bfd *abfd ATTRIBUTE_UNUSED;
 143 {
 144   return (BIN_SYMS + 1) * sizeof (asymbol *);
 145 }
 146
 147 /* Create a symbol name based on the bfd's filename.  */
 148
 149 static char *
 150 mangle_name (abfd, suffix)
 151      bfd *abfd;
 152      char *suffix;
 153 {
 154   bfd_size_type size;
 155   char *buf;
 156   char *p;
 157
 158   size = (strlen (bfd_get_filename (abfd))
 159           + strlen (suffix)
 160           + sizeof "_binary__");
 161
 162   buf = (char *) bfd_alloc (abfd, size);
 163   if (buf == NULL)
 164     return "";
 165
 166   sprintf (buf, "_binary_%s_%s", bfd_get_filename (abfd), suffix);
 167
 168   /* Change any non-alphanumeric characters to underscores.  */
 169   for (p = buf; *p; p++)
 170     if (! isalnum ((unsigned char) *p))
 171       *p = '_';
 172
 173   return buf;
 174 }
 175
 176 /* Return the symbol table.  */
 177
 178 static long
 179 binary_get_symtab (abfd, alocation)
 180      bfd *abfd;
 181      asymbol **alocation;
 182 {
 183   asection *sec = (asection *) abfd->tdata.any;
 184   asymbol *syms;
 185   unsigned int i;
 186   bfd_size_type amt = BIN_SYMS * sizeof (asymbol);
 187
 188   syms = (asymbol *) bfd_alloc (abfd, amt);
 189   if (syms == NULL)
 190     return false;
 191
 192   /* Start symbol.  */
 193   syms[0].the_bfd = abfd;
 194   syms[0].name = mangle_name (abfd, "start");
 195   syms[0].value = 0;
 196   syms[0].flags = BSF_GLOBAL;
 197   syms[0].section = sec;
 198   syms[0].udata.p = NULL;
 199
 200   /* End symbol.  */
 201   syms[1].the_bfd = abfd;
 202   syms[1].name = mangle_name (abfd, "end");
 203   syms[1].value = sec->_raw_size;
 204   syms[1].flags = BSF_GLOBAL;
 205   syms[1].section = sec;
 206   syms[1].udata.p = NULL;
 207
 208   /* Size symbol.  */
 209   syms[2].the_bfd = abfd;
 210   syms[2].name = mangle_name (abfd, "size");
 211   syms[2].value = sec->_raw_size;
 212   syms[2].flags = BSF_GLOBAL;
 213   syms[2].section = bfd_abs_section_ptr;
 214   syms[2].udata.p = NULL;
 215
 216   for (i = 0; i < BIN_SYMS; i++)
 217     *alocation++ = syms++;
 218   *alocation = NULL;
 219
 220   return BIN_SYMS;
 221 }
 222
 223 /* Make an empty symbol.  */
 224
 225 static asymbol *
 226 binary_make_empty_symbol (abfd)
 227      bfd *abfd;
 228 {
 229   return (asymbol *) bfd_alloc (abfd, (bfd_size_type) sizeof (asymbol));
 230 }
 231
 232 #define binary_print_symbol _bfd_nosymbols_print_symbol
 233
 234 /* Get information about a symbol.  */
 235
 236 static void
 237 binary_get_symbol_info (ignore_abfd, symbol, ret)
 238      bfd *ignore_abfd ATTRIBUTE_UNUSED;
 239      asymbol *symbol;
 240      symbol_info *ret;
 241 {
 242   bfd_symbol_info (symbol, ret);
 243 }
 244
 245 #define binary_bfd_is_local_label_name bfd_generic_is_local_label_name
 246 #define binary_get_lineno _bfd_nosymbols_get_lineno
 247 #define binary_find_nearest_line _bfd_nosymbols_find_nearest_line
 248 #define binary_bfd_make_debug_symbol _bfd_nosymbols_bfd_make_debug_symbol
 249 #define binary_read_minisymbols _bfd_generic_read_minisymbols
 250 #define binary_minisymbol_to_symbol _bfd_generic_minisymbol_to_symbol
 251
 252 #define binary_get_reloc_upper_bound \
 253   ((long (*) PARAMS ((bfd *, asection *))) bfd_0l)
 254 #define binary_canonicalize_reloc \
 255   ((long (*) PARAMS ((bfd *, asection *, arelent **, asymbol **))) bfd_0l)
 256 #define binary_bfd_reloc_type_lookup _bfd_norelocs_bfd_reloc_type_lookup
 257
 258 /* Set the architecture of a binary file.  */
 259 #define binary_set_arch_mach _bfd_generic_set_arch_mach
 260
 261 /* Write section contents of a binary file.  */
 262
 263 static boolean
 264 binary_set_section_contents (abfd, sec, data, offset, size)
 265      bfd *abfd;
 266      asection *sec;
 267      PTR data;
 268      file_ptr offset;
 269      bfd_size_type size;
 270 {
 271   if (size == 0)
 272     return true;
 273
 274   if (! abfd->output_has_begun)
 275     {
 276       boolean found_low;
 277       bfd_vma low;
 278       asection *s;
 279
 280       /* The lowest section LMA sets the virtual address of the start
 281          of the file.  We use this to set the file position of all the
 282          sections.  */
 283       found_low = false;
 284       low = 0;
 285       for (s = abfd->sections; s != NULL; s = s->next)
 286         if (((s->flags
 287               & (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC | SEC_NEVER_LOAD))
 288              == (SEC_HAS_CONTENTS | SEC_LOAD | SEC_ALLOC))
 289             && (s->_raw_size > 0)
 290             && (! found_low || s->lma < low))
 291           {
 292             low = s->lma;
 293             found_low = true;
 294           }
 295
 296       for (s = abfd->sections; s != NULL; s = s->next)
 297         {
 298           s->filepos = s->lma - low;
 299
 300           /* Skip following warning check for sections that will not
 301              occupy file space.  */
 302           if ((s->flags
 303                & (SEC_HAS_CONTENTS | SEC_ALLOC | SEC_NEVER_LOAD))
 304               != (SEC_HAS_CONTENTS | SEC_ALLOC)
 305               || (s->_raw_size == 0))
 306             continue;
 307
 308           /* If attempting to generate a binary file from a bfd with
 309              LMA's all over the place, huge (sparse?) binary files may
 310              result.  This condition attempts to detect this situation
 311              and print a warning.  Better heuristics would be nice to
 312              have.  */
 313
 314           if (s->filepos < 0)
 315             (*_bfd_error_handler)
 316               (_("Warning: Writing section `%s' to huge (ie negative) file offset 0x%lx."),
 317                bfd_get_section_name (abfd, s),
 318                (unsigned long) s->filepos);
 319         }
 320
 321       abfd->output_has_begun = true;
 322     }
 323
 324   /* We don't want to output anything for a section that is neither
 325      loaded nor allocated.  The contents of such a section are not
 326      meaningful in the binary format.  */
 327   if ((sec->flags & (SEC_LOAD | SEC_ALLOC)) == 0)
 328     return true;
 329   if ((sec->flags & SEC_NEVER_LOAD) != 0)
 330     return true;
 331
 332   return _bfd_generic_set_section_contents (abfd, sec, data, offset, size);
 333 }
 334
 335 /* No space is required for header information.  */
 336
 337 static int
 338 binary_sizeof_headers (abfd, exec)
 339      bfd *abfd ATTRIBUTE_UNUSED;
 340      boolean exec ATTRIBUTE_UNUSED;
 341 {
 342   return 0;
 343 }
 344
 345 #define binary_bfd_get_relocated_section_contents \
 346   bfd_generic_get_relocated_section_contents
 347 #define binary_bfd_relax_section bfd_generic_relax_section
 348 #define binary_bfd_gc_sections bfd_generic_gc_sections
 349 #define binary_bfd_merge_sections bfd_generic_merge_sections
 350 #define binary_bfd_link_hash_table_create _bfd_generic_link_hash_table_create
 351 #define binary_bfd_link_add_symbols _bfd_generic_link_add_symbols
 352 #define binary_bfd_final_link _bfd_generic_final_link
 353 #define binary_bfd_link_split_section _bfd_generic_link_split_section
 354 #define binary_get_section_contents_in_window \
 355   _bfd_generic_get_section_contents_in_window
 356
 357 const bfd_target binary_vec =
 358 {
 359   "binary",                     /* name */
 360   bfd_target_unknown_flavour,   /* flavour */
 361   BFD_ENDIAN_UNKNOWN,           /* byteorder */
 362   BFD_ENDIAN_UNKNOWN,           /* header_byteorder */
 363   EXEC_P,                       /* object_flags */
 364   (SEC_ALLOC | SEC_LOAD | SEC_READONLY | SEC_CODE | SEC_DATA
 365    | SEC_ROM | SEC_HAS_CONTENTS), /* section_flags */
 366   0,                            /* symbol_leading_char */
 367   ' ',                          /* ar_pad_char */
 368   16,                           /* ar_max_namelen */
 369   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 370   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 371   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* data */
 372   bfd_getb64, bfd_getb_signed_64, bfd_putb64,
 373   bfd_getb32, bfd_getb_signed_32, bfd_putb32,
 374   bfd_getb16, bfd_getb_signed_16, bfd_putb16,   /* hdrs */
 375   {                             /* bfd_check_format */
 376     _bfd_dummy_target,
 377     binary_object_p,            /* bfd_check_format */
 378     _bfd_dummy_target,
 379     _bfd_dummy_target,
 380   },
 381   {                             /* bfd_set_format */
 382     bfd_false,
 383     binary_mkobject,
 384     bfd_false,
 385     bfd_false,
 386   },
 387   {                             /* bfd_write_contents */
 388     bfd_false,
 389     bfd_true,
 390     bfd_false,
 391     bfd_false,
 392   },
 393
 394   BFD_JUMP_TABLE_GENERIC (binary),
 395   BFD_JUMP_TABLE_COPY (_bfd_generic),
 396   BFD_JUMP_TABLE_CORE (_bfd_nocore),
 397   BFD_JUMP_TABLE_ARCHIVE (_bfd_noarchive),
 398   BFD_JUMP_TABLE_SYMBOLS (binary),
 399   BFD_JUMP_TABLE_RELOCS (binary),
 400   BFD_JUMP_TABLE_WRITE (binary),
 401   BFD_JUMP_TABLE_LINK (binary),
 402   BFD_JUMP_TABLE_DYNAMIC (_bfd_nodynamic),
 403
 404   NULL,
 405
 406   NULL
 407 };